Higher wind speed in winter?

[CaptainPanic]

I found this map of the world, which shows wind speed in January and July (source: NASA). It clearly shows that in winter, wind speeds are higher than in summer, both on the northern and southern hemispheres.

 

To me, this seems counter intuitive. During summer, I would expect that there is more energy in the atmosphere, due to more energy from the sun. More energy -> higher wind speeds. Apparently, the opposite is true.

 

Does anyone know why this is, or does anyone feel like taking a guess?

 

[StringJunky]

There is much greater variation in barometric pressure during the winter than during the summer. On average, high pressure systems are higher pressure and low pressure systems are lower pressure. This leads to a more rapid flow of air between the systems. This fluctuation is caused by much greater variation in temperature during the winter. While most summer days are roughly the same temperature, winter temperatures fluctuate dramatically.

 

 

The charts linked below show the seasonal variation in temperature, barometric pressure, and wind speed for New York City in 2008. Note how as temperatures become more stable from May to October, barometric pressure also becomes more stable, and wind speeds decrease.

 

 

Source: http://wiki.answers.com/Q/Why_is_it_windier_in_the_winter_than_in_the_summer

 

Just my unqualified thought: Molecules move from high pressure to low pressure…if you are situated in a low pressure area there are more opportunities for greater temperature and pressure gradients than standing in a high pressure area and thus you will have the wind coming at you more often.

Edited September 21, 2012 by StringJunky